This invention relates to a power-operated valve with a pair of rotary valve plates which opens or closes by disposing a pair of spherically-shaped valve plates tightly onto the valve seats of the valve casing.
With respect to large-sized power-operated valves which are used in power plants or chemical plants for regulating a gaseous or fluid body and which virtually necessitate the remote control thereof, conventional valves cannot be regulated with promptness and tight sealing. In general, conventional power-operated valves are driven by either a pneumatic operating means or an electrically-operating means. In these conventional electrically-operated valves, the rotation and urging of the valve plates against the valve seats are conducted by one motor for effecting rotation and another motor for urging the valve plates against the valve seals so that the valve has a considerably intricate or complicated construction.
In conventional pneumatically-operated valves, there is also the disadvantage that since the pneumatic cylinder mechanism moves upwardly or downwardly and rotates relative to the valve casing, the air supply hoses attached to the side of the cylinder are repeatedly slackened and tightened so that the hoses are worn or broken and cause leakage of working air.
Furthermore, due to the above construction, the valve requires a considerable total valve height resulting in an inconvenience and disadvantage in the mounting of the valve.
In addition, the valve-plate actuating mechanism which is disposed within the valve has the disadvantage that the movement of the valve shaft is not smoothly interlocked with the movement of the valve plates so that seizure or damage of the valve-plate actuating mechanism occurs.
Accordingly, it is an object of the present invention to provide a power-operated valve which will overcome the aforementioned disadvantages of conventional valves.
It is another object of the present invention to provide a power-operated valve which overcomes the mentioned disadvantages of conventional valves wherein the valve is characterized by a single power-operated motor which is capable of both rotating the valve plates and urging the valve plates against the valve seats of the valve whereby the valve has a simple construction.
It is still another object of the present invention to provide, according to one embodiment of the present invention, a pneumatically-operated valve which overcomes the aforementioned disadvantages of conventional valves and which is characterized in that a power cylinder is mounted on the valve casing so that the air piping can be attached in a stationary position, thereby obviating the problems related with air piping, and the total valve height can be minimized facilitating the easy installation of the valve in any place and furthermore, a specially devised valve-plate actuating mechanism enables the smooth interlocking relationship between the movement of the valve shaft and the valve plates.
The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein two embodiments are illustrated.